Aminonitriles are a class of important chemicals that have a variety of industrial applications. For example, aminonitriles can be used as monomers for producing high molecular weight polyamides. Specifically, 6-aminocapronitrile can be used to produce nylon 6.
Aminonitriles can be produced by catalytic partial hydrogenation of dinitriles. See, for example, U.S. Pat. No. 2,208,598, U.S. Pat. No. 2,257,814, U.S. Pat. No. 2,762,835, U.S. Pat. No. 3,322,815, U.S. Pat. No. 3,350,439, U.S. Pat. No. 3,591,618, U.S. Pat. No. 4,389,348, U.S. Pat. No. 4,601,859, U.S. Pat. No. 5,151,543, U.S. Pat. No. 5,296,628, U.S. Pat. No. 5,512,697, U.S. Pat. No. 5,527,946, DE836938, DE848654, DE-A-19636768 and WO99/47492, all of which are incorporated by reference herein for all purposes as if fully set forth. However, the yield of and selectivity to a desired aminonitrile using some of the known processes may not be as high as desired, and the amount of the complete hydrogenation product (diamine) is also generally higher than desired.
WO99/47492 mentioned above describes the use of certain carbonyl group-containing compounds as additives in the partial hydrogenation process to improve the yield of and/or selectivity to the desired aminonitrile product, and/or reduce the amount of fully hydrogenated product (diamine) produced.
We have now found new classes of compounds that also effectively function as improved yield and/or selectivity additives in the partial hydrogenation processes such as, for example, those mentioned in previously incorporated WO99/47492.